Support delayed AudioUnit initialization.

webrtc/examples/objc/AppRTCDemo/ios/ARDMainView.h

 /*
  *  Copyright 2015 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #import <UIKit/UIKit.h>
 
 @class ARDMainView;
 
 @protocol ARDMainViewDelegate <NSObject>
 
 - (void)mainView:(ARDMainView *)mainView
-    didInputRoom:(NSString *)room
-      isLoopback:(BOOL)isLoopback
-     isAudioOnly:(BOOL)isAudioOnly;
+             didInputRoom:(NSString *)room
+               isLoopback:(BOOL)isLoopback
+              isAudioOnly:(BOOL)isAudioOnly
+   shouldDelayAudioConfig:(BOOL)shouldDelayAudioConfig;
+
+- (void)mainViewDidToggleAudioLoop:(ARDMainView *)mainView;
 
 @end
 
 // The main view of AppRTCDemo. It contains an input field for entering a room
 // name on apprtc to connect to.
 @interface ARDMainView : UIView
 
 @property(nonatomic, weak) id<ARDMainViewDelegate> delegate;
+// Updates the audio loop button as needed.
+@property(nonatomic, assign) BOOL isAudioLoopPlaying;
 
 @end